Hydraulic power transmission for use with rotatable engine-driven power take-off shafts



2 Sheets-Sheet 1 MARTIN ENGINE DRIVEN POWER TAKE-OFF SHAFTS HYDRAULIC POWER TRANSMISSION FOR USE WITH ROTATABLE lllllllllf"""" lll May 22,

Filed Feb. 15, 1947 f-f/'rORA/fx 2 Sheets-Sheet 2 f/VVf/Vrw? MARTIN HYDRAULIC POWER TRANSMISSION FOR USE WITH ROTATABLE ENGINE DRIVEN POWER TAKE-OFF SHAFTS 1947 Filed Feb. l5,

May 22,V 1951 Patented May 22, 1951 UNITED ST'lES Arre HYDRAULIC POWER TRANSMISSION FR USE WITH ROTA'ABLIEI 'ENGINE-DRIVEN POWER TAKE-OFF SHAFTS Charles H. Martin, Huntington Vllark, Calif., as-

signor, by mesne assignments, to Farm-Aid Implement Company, Norwalk, Calif., a corporation ci ACalifornia Application February 15, 1947, Serial No. y'728,815

mounted on an automotive vehicle having ground working implements connected thereto, and which provides a means for converting thepower vof an engine-driven rotating shaft into hydraulic power and then utilizing such'hydraulic power to actuate a remote power lift on the implement. Specifically, the present invention was designed for use on the small, four-wheel drive, personnel carrying vehicle developed for the military services and known popularly as the ,ieep. vBecause of its light weight, four-wheel drive, and generally rugged construction, the jeep has been found to be ideally suited for use on small farms las a utility'vehicle, and is extensively employed as a tractor to pullground working implements of all kinds. The versatility `oi the postwar jeep has been enhanced still further by the addition oi an engine-driven power take-oil shaft, making it possible to drive equipment such as saws, threshers, hammermills, air compressors, and the like. There is one shortcoming of the jeep, however, and thatis its lack 'of any provision for the actuation of hydraulic power lift equipment on 'the implement. As aresult, implements designed for the jeep have generally'been'limited to manually operated lifting levers or mechanical lifts utilizing wheel-driven half-revolution clutches, neither 0f which is as satisfactory for certain classes of equipment as the hydraulic power lift.

One of the principal objects of the present linvention, therefore, is "to provide a new and improved hydraulic power transmission device adapted to be mounted on ra propelling vehicle and driven by the engine thereof to provide a lsource of fluid pressure for actuating 'hydraulic equipment on the vehicle or implement.

Another important object of the invention is to Lprovide a self-containedvpower lift 4mechanism which'is adapted to be driven from the power take-off shaft of a `jeep or other .automotive Vehicle, and which vrequires-no structural alteration .of the vehicleor its transmission system.

Another object rof the .invention is to provide aidevice -for lgenerating fluid pressure, in which the fluid is vacted upon only during the power stroke and is not constantly circulated with resultant loss of power, asin prior devices.

A -further object of the invention is to provide a-device of the class described in which the generation of fluid pressure for the power stroke is started or `stopped by engaging or disengaging'a clutch, thereby eliminating the need for the usual'valves.

Another object is to provide a hydraulic power transmission device in which the generation of pressure is automatically stopped and held at the end of the power stroke so that the system is protected against the development of excessive pressures without relying on pressure relief by-pass valves.

Still another object of the invention is the provision of a hydraulic power lift device embodying means whereby the implements may be dropped quickly to ground-working position.

These objects are achieved in the present invention by the provisionv of a vreversible gear transmission which 'is adapted to be connected to the power take-oil shaft to be driven thereby and which is operative to drive a piston :axially within ua `master cylinder to displace fluid contained therein. The displaced fluid is conveyed through a line to the working cylinder of a remote hydraulic power lift or other operating mechanism to Vactuate the same, and operation'of the device is accomplishedby engaging one of-two Yclutches to drive the piston in one direction or 'the other.

A valve is provided in the system for lay-passing hydraulic fluid from 'the wor-king 4cylinder to a reservoir tank when it is desired to drop the implements quickly to ground-working position. In this way', fluid inthe working cylinder can be displacd more rapidly by the piston than if it weredrawn onc by the master cylinder, vthere-- by permitting a fast return of the working piston with a correspondingly quick drop of'the implements carried thereby. The flud in the reservoir tank is then drawn into the master cylinder through a ycheck valve.

The above and other objects and advantages of theinvention will become apparent to those skilled in the art upon consideration of the following detailed descriptionof the preferred-embodiment thereof, reference being had to the `drawings in which:

Figure 6 is an enlarged sectional view of the vaive which is connected to the fluid line and which permits the implements to drop quickly to their operative, ground-working position.

In the drawings, the rear end of the body of the vehicie to which the device is attached is designated by the reference numeral lil, and projecting rearwardly therefrom is a splined power takeoff shaft H which is driven from the engine of the vehicle, The hydraulic power transmission device of the invention comprises a gear box I2 which is adapted to be mounted on the vehicle body i@ by brackets i3; a master cylinder I4 having a piston i5 connected to the gearing in the box i2 to be moved thereby; and a working cylinder i6 which is connected by a flexible hydraulic line l? to the master cylinder. A piston lil in the cylinder le is operatively connected to mechanism on the implement (not shown) to actuate the same.

The gear box i2 includes a generally rectangular housing 2D having bushings 2l at opposite ends thereof, which serve as journals for a shaft 22. The shaft 22 projects forwardly through the front wall of the housing 2E! and has a sprocket f 23 xed to its outer end, which is connected by a chain 24 to a drive sprocket 25 mounted on the splined power take-off shaft I l. Between the two bushings 2l, the shaft 22 is enlarged in diameter at 26 and splined at 21 and 28 to receive the correspondingly splined hubs of the driving members 3B and 3| of clutches 32 and 33, respectively. The two clutches 32, 33 are shown illustratively as cone clutches, but it will be understood, of course, that any other form of clutch might be used with equal advantage. The clutch driving members 3G, 3! are slidable on their splines 21, 28 for movement into and out of engagement with driven members 3d and 35 which are fixedly mounted on tOrque tubes 35i and 3l'. The torque tubes 36, 3l are rotatably mounted end to end on the enlarged portion of the shaft, and are supported at their adjacent ends in ball bearings fli) which are held in a common bearing support member 4l extending transversely across the housing 25) from one wall to the other. The front torque tube is additionally supported by a ball bearing 42 mounted in a support member 43, while the rear torque tube 3l is held by a ball bearing 5.4 mounted in a support member 45.

Fixedly mounted on the front torque tube 3S between the bearings le and 42 is a gear 46 which meshes with a companionate gear 5@ mounted on a tubular shaft 5i disposed below the shaft 25 and parallel thereto. The tubular shaft 5l is journaled at its ends in bushings 52 and 53 which are mounted in the end walls of the housing 2S, and is provided with an internal thread 54 extending from one end to the other. Slidably disposed within the tube 5i and projecting from the rear end thereof is a rod 55 having raised threads 56 at its inner end which mesh with the threads 54 of the tube. The rear end of the rod 55 extends into the master cylinder ii and is provided with a threaded stud @El of reduced diameter. A circular plate 5i is mounted on the stud 60 abutting against the shoulder formed at the junction of the stud with the rod, and clamped between the plate 6i and a washer S2 is a cup 63 of leather or rubber, having a. rearwardly directed annular flange which bears against the inside wall of the cylinder. A nut 54 is threaded on the stud 6i and serves to draw the washer E2 tight against the cup.

The rear torque tube 3l has a driving sprocket al' xed thereto between the bearings 40 and 44, said sprocket being connected by a chain S3 to a driven sprocket 55 mounted on the tube 5l. The purpose of the sprocket drive 6l, 68, 69 is to drive the tube 5I in one direction from the torque tube 37, while the gears 46, 55 serve to drive the tube 5i in the other direction from the front torque tube 35, both torque tubes being rotatable in the same direction when connected with the shaft 26 through their respective LSU clutches 3Q and 35. Thus the piston I5 can be driven toward the rear end of the master cylinder M by engaging one of the clutches 34, 35 to rotate the tube 5i in one direction, or toward the front end of the master cylinder by engaging the other clutch. Rearward movement of the piston I5 causes a positive displacement of the fluid contained in the rear end of the master cylinder i4, and this displaced fluid is transmitted through the line Il to the right hand end of the working cylinder I6 to drive the piston I8 forwardly. Since the working cylinder l is usually connected to a power lift and is therefore loaded in one direction only, it is not necessary to provide for the application of fluid pressure to the opposite side of the piston to return the same to the right hand end of the cylinder I5. Fluid in the right hand end of the working cylinder It is placed under pressure from the load applied on the piston i8 by the weight of the raised tools, and is forced back through the line I1 as the master cylinder piston le is moved to the left. If it should be desirable to have a two-way power stroke of the working piston I8, it is necessary only to provide another line connecting the left hand end of the master cylinder I4 with the left hand end of the working cylinder I5; addy another cup to each of the pistons facing toward the left so that the pistons will hold pressure from either direction; and fill both sides of both cylinders with hydraulic fluid.

Selective engagement of the clutches 30, 3l is effected through a lever 13 which is pivoted at 'I4 on an upstanding bracket I5 on the top cover plate 'I6 of the housing 2b. At its bottom end, the lever 'i3 is provided with a pin ll which passes through an elongated slot 'I3 formed in a bracket 8B xed to a bar 8i. The bar 8| is disposed on the inside of the housing 2i) and the bracket 8! projects upwardly therefrom through a slot 32 in the cover plate. The bar 8l is slidably held against the bottom surface of the plate 'I6 by two longitudinally spaced guide brackets 83 and 84, and the ends of the bar are bent downwardly and provided with forks 8l which engage annular grooves 85 and B in the clutch driving members 3D, 3i, respectively. Thus, when the lever 13 is shifted forwardly to the position indicated in dot-dash lines at A, the bar 8! is moved rearwardly, engaging the driving member 39 of clutch 32 with its driven member 34, while at the same time, the driving member 3l of clutchv 53 is separated still further from its driven member. With the clutch 32 thus engaged, power from the shaft 25 is transmitted to the front torque tube 35 and through gears 46, 50 to drive the tube 5l in one direction, causing the rod 55 to be moved to the right, or left, depending upo'n the direction of rotation of the shaft 26 and the lead of threads 54. When the lever 13 is swung rearwardly to the position indicated at B, however, the driving member 3i of clutch 33 is engaged with its driven member 35, while the driving member 3Q of clutch 32 is separated from its driven member 34. In this condition, power from accese@ vthe shaft 26 is transmitted through clutch v33 to the rear torque tube 31 and thence through sprockets 61 and 69 to the tube 5I. Since the sprocket SS turns in the saine direction as sprocket (il, whereas gear 50 turns in the opposite direction to gear d5, rotation of the tube 5| when driven by the sprockets is in the opposite direction to that when driven by the gears. With the tube 5i thus turning in the other direction, the rod 55 is moved in the-opposite direction to that traveled when the drive is through the gears.

In order to prevent the rod 55 from iturning with the tube 5I, an arm 9i? Vis Aiixedly mounted on the rod 55 between the housing 2Q and master cylinder It and projects upwardly therefrom. The top end of the rod passes through an -elongated slot Si formed in a rearwardly projecting bar 92 slidably mounted on the top surface of the cover plate "l parallel to the rod 55. The

bar 82 is slidably held by a guide bracket 9,3 -xed to the top surface of the plate 'I at its rear edge, and projecting upwardly and forwardly from the front end of the bar 92 is an arm 2liwhich is connected by a pin 95 to the lever 'i3 above the pivot pin le.

In the illustrative form of the invention shown, the rod 55 is caused to move to the right when the lever 'i3 is shifted to position A, and as thc master cylinder piston I5 approaches the end or" its travel in this direction, the arm i engages the right hand end of the slot 5| in bar 92. At

'this 4.point the lever 'I3 s'zpic'ked .up by the arm 9@ and shifted forwardly to its :center neutral position, disengaging clutch 32 whichas pointed out previously, is engaged when the lever is at position A. With the power to the 'tubular-drive shaft 5| thus cut oi, piston I5 cornes to a stop and `there is no further displacement of fluid fromvthe right hand end of the master cylinder iii.

Since the arm 9i! Yis now engaged by the right hand end of the slot l, the lever 'i3 is Aprevented from moving to the left or back toward position A, and the only direction of control movement available is toward position B. When the lever is swung over to position B, clutch 33 isengaged, moving the rod 55 and piston I5 to the left. As the piston I 5 approaches 'the end of its travel in this direction, the .arm ed engages. the left hand end-of slot 9i and moves the lever i3 Jback to .neutral position again to discngage the clutch and bring the piston I5 to a stop. The pitch of the threads Sli is such that the driving connection between tube 5| and rod 55 is irreversible in nature, and no amount of thrust by the piston I5 on rod 55 will produce rotation of the tube 5|.

A by-pass arrangement is provided to permit the fast return or the working piston |8 to thc right hand end of the cylinder I6 so that implements may be dropped quicly from raised position to ground-working position. The function of this by-pass arrangement is to provide means for receiving the entire volume of fluid displaced from the right hand end of the working cylinder by the implement-loaded piston and holding the iiuid until the same has been drawn into the master cylinder I4 by the relatively slowmoving piston I5. Accordingly, the by-pass includes a T-connection lili! which is connected into the line Il and which has a branch line It! leading to a valve |82. A line |03 extends from the valve H32 to the upper end of a reservoir tank It, with which it is connected. Another line Ii is connected to the lower end of -of an equalizer bar I2I.

tively slow rtravel toward the left.

the tank Hill and to the yright hand end of the master cylinder I through 4a check valve ii.

The valve |32 may be of any desired type, and is shown typically as comprising a housing having fluid passages provided therein which vcommunicate with the lines Ii and Ii. Slidably disposed within the housing is a valve poppet I II which is yieldingly held onto its seat by a spring II2. At its upper end, the stem of the valve poppet I I I is connected by a pin I I3 to one arm of a bell-crank H which is pivoted at |I5 on a bracket Ili on the valve housing. The upwardly extending other arm of the bell crank is connected to a push-pull rod |29 which extends forwardly therefrom and is connected to one end The other end of the equalizer bar is connected by a link I2?. to the clutch lever 13. Pivotally connected to the equalizer bar |2| between the rod I2@ and link |22 is a forwardly extending link |23 which is connected at its front end by a pin I 2t to a manually operable control handle |725 pivoted at 26 on a bracket I2? mounted on the vehicle body I.

The linkage arrangement described above enables the operator to shift the clutch lever '.13 back to position B and simultaneously open the valve Il2 Iby merely moving the one control handle |25 rearwardly. The equalizer bar I 2| distributes the control movement of the handle |25 between the `clutch lever i3 and valve-actuating-bell crank lill according 'to their respective needs, and takes care of the difference in their operational movement. With the lever "i3 moved back to position B, the forward clutch 32 is engaged, causing the piston l5 to begin its rela- At the same time, however, the simultaneous opening of the valve |92 permits iiuid from the working cylinder Ile to empty yrapid-ly into the reservoir tank IGA under'the pressuresexerted'by the implementloaded piston IS, and as Va lresult the implements are dropped quickly to ground-engaging position. The fluid discharged into the reservoir tank los is then drawn into the master cylinder ill through the line itii and check valve Ifile by the slow- .moving piston 'I5 until the latter reaches the end of its travel.

When the control handle i25 is pulled forwardly, the lever 'i3 is shifted to position A to .drive the piston .i5 rearwardly. Since the valve .puppet I II is normally seated,'the bell crank i is :prevented from rocking in acounterclockwise direction, and the rod 2ll is therefore held stationary. During rearward movement of the piston l5, fluid from the master cylinder is prevented from discharging into the reservoir tank |34 by the check valve |36.

The operation and advantages oi the present invention are believed to be self-evident from the foregoing discussion. Since the fluid in the master cylinder lll is acted upon only during the power stroke when one of the clutches 32, 33 is engaged, there is no loss of power from constant circulation of the iiuid as in prior devices. The device may be used in one form as a self-contained hydraulic power transmission mechanism in which the gear box I2, master cylinder It, and working cylinder l5 are all integrally mounted on an implement and the only connection with the vehicle is to the power take-on shaft II by the sprockets 23, 25 and chain 24. Alternatively, the device may be used in another manner as a source of fluid pressure for working cylinders mounted on several different implements, and in this case the gear box I2 and master cylinder I4 would be mounted on the vehicle more or less permanently and removed therefrom only when required by convenience. When the device is to be used in this manner, a quick detachable fluid line coupling 9S may be provided at the discharge end of the master cylinder i4 to receive a coupling member Sl on the line il', so that the line may be quickly and easily connected to the master cylinder. 'Such a coupling should preferably be of the type employing a double check valve to prevent loss of fluid from either the cylinder l or line il when the latter is disconnected.

While I have shown and described in some detail what I consider to be the preferred form of my invention, it is to be unde-rstood that changes may be made in the shape and arrangement of the several parts without departing from the broad scope of the invention as deiined in the appended claims.

I claim:

1. A hydraulic power lift device for use with a vehicle adapted to have ground-working implements mounted thereon for movement between raised and lowered positions, and said vehicle having an engine-driven power take-oil shaft, said power lift device comprising a master cylinder and piston, a working cylinder and piston, reversible transmission means operatively connected with said power take-01T shaft for driving the piston in said master cylinder from one end thereof to the other, a hydraulic line connecting one end of said master cylinder with one end of said working cylinder whereby fluid displaced by the movement of the piston in the master cylinder is conveyed to the working cylinder to move the piston therein, said working piston being adapted to be connected to said implements to raise or lower the same, a reservoir tank connected to said hydraulic line, valve means opera-- tive to by-pass fluid from said working cylinder to said reservoir tank to permit the fast return of the implement-loaded working piston, and a check-valve controlled return line from said reservoir tank to said master cylinder, said master cylinder drawing iiuid from said reservoir tank until the piston has reached the end or its return travel.

2. A hydraulic power lift device i'or use with a vehicle adapted to have ground-working implements mounted thereon for movement between raised and lowered positions, and said vehicle having an engine-driven power take-off shaft,

said power lift device comprising a master cylinder and piston, a working cylinder and piston, a reversible drive mechanism operatively connected with said power take-off shaft, a .screw threaded member supported for rotation, a rod connected at one end to the piston in said master cylinder and having threaded connection with said screw member, whereby said piston may be driven in one direction or the other within the master cylinder, a hydraulic line connecting one end of said master cylinder with one end of said working cylinder whereby fluid displaced by the move.1 ent of the piston in the master cylinder is conveyed to the working cylinder to move the piston therein, said working piston being adapted to be connected to said implements to raise or lower the same, a reservoir tank, valve means for by-passing fluid from said hydraulic line to said reservoir tank to permit the fast return of the implementloaded working piston, a check-valve controlled return line from said reservoir tank to said master cylinder, said master cylinder drawing iiuid from said reservoir tank until the piston has reached the end of its return travel, control means operatively connected to both said reversible drive mechanism and to said valve means whereby said master cylinder piston is started on its return stroke and said valve means is simultaneously opened.

CHARLES H. MARTIN.

REFERENCES CITED The following references are of record in the rile of this patent:

UNITED STATES PATENTS Number Name Date 865,201 Morton Sept. 3, 1907 1,439,304 Fraser Dec. 19, 1922 1,754,688 McFarlane Api". 15, 1930 1,885,936 Bowen Nov. 8, 1932 1,983,884 Hele-Shaw Dec. 11, 1934 2,252,482 Gates Aug. 12, 1941 2,322,133 Hettelsater June 15, 1943 2,361,326 Silver Oct. 24, 1944 2,433,990 Hardy Jan. 6, 1948 2,481,477 Peery Sept. 6, 1949 2,487,699 Fiegel Nov. 8, 1949 FOREIGN PATENTS Number Country Date 41,164 Denmark |Nov. 16, 1929 440,087 Germany Jan. 28. 192'..7 

